THE planter's GUIDE. 



75 



brief and popular modification now given of protecting 

 and non-protecting properties, is not perhaps strictly 

 philosophical ; but it is adopted merely on account of its 

 simplicity, and for the purpose of accommodating the 

 theory to practice. These properties, I am aware, are 

 acquired by trees solely in consequence of differences in 

 their situation ; and for that reason it might have been 

 better, if terms could have been found having a reference 

 to what the tree is, or to the conditions that have made it 

 so, rather than to any future uses which the character 

 thus acquired is considered to serve. But they may be 

 defended precisely on the same grounds as the terms 

 " conducting" and " non-conducting,'' as applied to certain 

 substances capable of receiving and transmitting the 

 electric fluid, which were first invented by DisagTiliers, 

 and have been since admitted into the philosophical 

 nomenclature. 



The above practical view, however, with the illustrations 

 already ofibred, cannot well mislead us, as they are founded 

 on admitted doctrines of phytology and the laws of nature. 

 If such a mode of execution be superinduced upon it as 

 shall furnish to the tree a competent supply of sap at the 

 critical period of removal, the art may be said to be 

 established on fixed principles ; and thus the results may 

 be rendered as certain and successful as the severity of 

 the operation will admit. Of the general correctness of 

 the theory there seems little doabt ; but, like every other 

 drawn from nature, it will be still further developed and 

 improved by observation and experience. I may, how- 

 ever, say, after considerable experience, that, in park- 

 practice at least, it admits of few modifications and no 

 exceptions. 



It is both interesting and important to observe, that 

 the principles on which this theory is founded are the 



